Building a 273

273Dynamite said
Hi,
im building a 1969 273 with a 904 automatic trans for my 2 door 1949 Plymouth.
its a stock 2 barrel carb i believe 180-190 horsepower. Me and my uncle want to build it to the super commando specs ranking in at 275 horsepower but trying to push it up to 300 horsepower. I acquired a '65 Commando intake #2465726View attachment 1715959407 View attachment 1715959407 , Im not sure if that will fit on a '69 block. I know i could use the Edelbrock LD4B intake but would like to see if i can use the '65 commando intake. Also have a '64 8 3/4 rear end for the Plymouth, should bolt right in, its an inch bigger than original rear end. Just wanted to see anyone else's input on this build and get any other opinions and options for it. thanks! ...

A "69" 273 is a good start. The pistons should be .03 higher in the block than the 64-67 2 barrel pistons to make up for the open chambered heads. It is near a zero deck engine. It also should have 675 heads and a cast crank. No problem at all with the cast crank. Sell the intake to some one who has a 64 or 65 273. You can use any intake made for a 66 up 273 or 67 up 318, 340 or 360. That TQ intake would work in the picture. If you need to get new pistons, keep the open chambered heads to bring the compression down to use pump gas. Use Stainless Steel 1.50 exhaust valves. You should pull the valve covers and check what head castings you have and if you have hydraulic rocker arms.